Cam options for 1.8 B series

Bazmatronic · Post by **Bazmatronic** » Sun Mar 14, 2021 8:56 pm

Evening all
I’ve got a plan to take a stock 1.8 B series, and use a set of HS4 twin SU’s on it. When I do it, I want to put a warmer cam in too, and have the dizzy recurved to match the cam.
So, my question is, which cam? The plan is to build a 1.8 saloon that will cruise dual carriageways and motorways easily, as I’m south coast based and shows always seem to be miles away. I’m not looking to build a race car, and defo don’t want a cam that idles like a tractor, the car will be used around town in traffic as well as cruising the fast roads.
Let me know what you think!
Cheers
Baz

Post by **MarinaCoupe** » Sun Mar 14, 2021 10:08 pm

I used a Piper 270 cam in mine with a pre 1967 MGB Lucas 25D distributor as the advance curve suits the camshaft. I used K&N filters and found that AAA needles worked best in the twin HS4 carbs.

Tickover was OK, just a little lumpy. It’s worth getting some basic gas flowing done, particularly in the exhaust port. I used standard early Marina 1.8 inlet and exhaust valves and had the valves and seats three angle cut.

If you are doing a lot of motorway and dual carriage way driving then you will be using fairly high revs, so its worth thinking about double valve springs and if you do, then use a duplex timing chain as the double springs put more strain on the valve gear train.

Post by **PHUQ** » Mon Mar 15, 2021 12:21 pm

I've got a 285 in mine and I'm expecting it to be a bit on the lumpy side, that's with a Peter Burgess fast road head (with the factory "big valves" from the early 70's). Currently it's still in the inlaw's garage, I'll report back hopefully later this year! I've got one of the fully mappable 123 distributors on the way that will hopefully help to tame some of the bottom end roughness. Duplex chain with a vernier pulley. That'll be with twin HS4s of course.

Post by **balmy** » Mon Mar 15, 2021 5:01 pm

Initially a 255 in my TC. Flat torque curve-ideal for everyday use and easy overtaking.

Post by **PHUQ** » Mon Mar 15, 2021 7:49 pm

balmy wrote: ↑Mon Mar 15, 2021 5:01 pm Initially a 255 in my TC. Flat torque curve-ideal for everyday use and easy overtaking.

You've got a few more cc's than everyone else mind

locost_bryan · Post by **locost_bryan** » Mon Mar 15, 2021 8:14 pm

MarinaCoupe wrote: ↑Sun Mar 14, 2021 10:08 pm I used a Piper 270 cam in mine with a pre 1967 MGB Lucas 25D distributor as the advance curve suits the camshaft. I used K&N filters and found that AAA needles worked best in the twin HS4 carbs.

Does that distributor have vacuum advance? (Can never remember which MGBs had what)

Post by **MarinaCoupe** » Mon Mar 15, 2021 10:51 pm

Yes Bryan with vacuum advance.

locost_bryan · Post by **locost_bryan** » Tue Mar 16, 2021 9:38 pm

Cool, that ties in well with the recommendation from the other thread about vacuum advance improving economy at cruising speeds.

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